Which bacterium is responsible for causing the serious infection known as the plague?

The bacterium responsible for causing the serious infection known as the plague is Yersinia pestis. This pathogen is notorious for causing historical pandemics, including the Black Death in the 14th century, which resulted in millions of deaths across Europe and Asia. Yersinia pestis is primarily transmitted through flea bites but can also spread through direct contact with infected animals or bodily fluids. Understanding the role of Yersinia pestis is crucial for epidemiology and public health, particularly in addressing outbreaks and managing the risks associated with this infectious disease. Other bacteria listed, while notable in their own right, are associated with different infections; for instance, Streptococcus pneumoniae is known for pneumonia, Escherichia coli is often linked to foodborne illness, and Vibrio cholerae causes cholera.